Symbol indication device

ABSTRACT

A device comprising a mask plate having formed therein at least one symbol indication window comprising at least one relatively narrow and elongated quadrilateral slot or slit and having an inclined base line, a symbol indicator having at least one series of symbol patterns printed or otherwise superposed thereon, and symbol indicator drive means. The symbol indicator drive means intermittently drives and moves the symbol indicator in such manner that the latter is moved a distance corresponding to one half the length of each symbol pattern each time it is driven, whereby one symbol after another can be indicated through the symbol indication window.

United States Patent [191 Funaki [111 3,831,303 [451 Aug. 27, 1974 1SYMBOL INDICATION DEVICE [75] Inventor: Takashi Funaki, Nagano, Japan 22Filed: Aug. 31, 1972 21 App]. No.: 285,433

[30] Foreign Application Priority Data Nov. 18, 1971 Japan 46-91904 Dec.25, 1971 Japan 47-1066 Jan. 14, 1972 Japan 1 47-5863 Jan. 14, 1972 Japan47-5864 Jan. 28, 1972 Japan 47-9803 7 Sept. 2, 1971 Japan 46-78885 [52]US. Cl. 40/28 C, 58/125 C, 235/117 [51] Int. Cl. G09f 11/00 [58] Fieldof Search 40/28 C, 68, 77.4, 77.6, 40/777, 77.8, 77.9, 96, 96.5;235/117; 58/125 C, 127 R [56] References Cited UNITED STATES PATENTS2,585,420 2/1952 Ailes 40/774 3,292,289 12/1966 Fuhr 40/96 3,344,54410/1967 Hellen 40/68 3,399,474 9/1968 Rinder 40/28 C 3,200,396 8/1965Stevens etal 340/378 R 3,444,552 5/1969 Feign 340/378 RX PrimaryExaminerWm. H. Grieb Attorney, Agent, or FirmMcG1ew and Tuttle ABSTRACTA device comprising a mask plate having formed therein at least onesymbol indication window comprising at least one relatively narrow andelongated quadrilateral slot or slit and having an inclined base line, asymbol indicator having at least one series of symbol patterns printedor otherwise superposed thereon, and symbol indicator drive means. Thesymbol indicator drive means intermittently drives and moves the symbolindicator in such manner that the latter is moved a distancecorresponding to one half the length of each symbol pattern each time itis driven, whereby one symbol after another can be indicated through thesymbol indication window.

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SYMBOL INDICATION DEVICE BACKGROUND OF THE INVENTION This inventionrelates to a symbol indication device.

In clocks of the digit indication type, it is required to indicate onenumerical symbol after another or one day of the week after another astime elapses. In metersof other instruments, it is required to indicateone numerical symbol after another or one letter after another dependingon the use to which it is put. It has hitherto been customary to employvarious types of symbol indication devices in these apparatus.

In one type of symbol indication devices known in the art, there areprovided a mask plate formed threin with at least one symbol indicationwindow which comprises at least one slit or slot, a symbol indicatorhaving at least one series of symbol patterns, and symbol indicatordrive means. The symbol indicator is intermittently driven and moved bythe symbol indicator drive means in such manner that each symbol patternis moved a distance corresponding to its length so that the symbols canbe indicated successively through one of the symbol indication windows.

The symbol indicator is usually in the form of a drum, or cylinder, or abelt on which at least one series of symbols patterns are printed orotherwise superposed. The symbol indicator of this type is relativelyeasy to drive. Thus, symbol indication devices using this type of symbolindicator offer the advantages of being more compact in size and lowerin production cost than other symbol indication devices such as, forexample, those using blades.

When it is required to increase the size of symbols indicated by asymbol indication device using a mask plate and a symbol indicator,there is a disadvantage in that the diameter of the drum or the lengthof the belt serving as the symbol indicator should be increased. Thisincreases the dimensions of the device.

Stevens, et al., US. Pat. 3,200,396, issued Aug. 10, 1965, disclosesdrums carrying a series of characters, such a numbers, letters orcombinations of letters and numbers. In the Stevens, et al. patent,portions of some adjacent symbols are common to both adjacent symbols,so that the symbol displayed in a display window is composed of twoimmediately adjacent symbols having overlapping portions in common witheach other.

SUMMARY OF THE INVENTION An object of this invention is to provide asymbol indication device comprising a mask plate and a symbol indicatorwhich permits to increase the size of symbols indicated through thewindow without increasing the dimensions of the device by arranging aplurality of series of symbol patterns on the symbol indicator in suchmanner that one-half portions of the adjacent symbol patterns ofoneseries overlap one another and intermittently moving the symbolindicator relative to the mask plate a distance corresponding to onehalf the length of each symbol pattern whereby one symbol after anothercan be indicated through one of the windows.

In the present invention, a symbol indication window or windows formedin the mask plate and each comprising at least one relatively narrow andelongated quadrilateral slot or slit and one or a plurality of series ofsumbol patterns printed or otherwise superposed on the symbol indicatorhave respective base lines which are inclined, so that the symbolsindicated through the windows are in an inclined position. This is oneof the features of this invention. That is, by arranging the symbolindication window or windows and the series of symbol patterns in aninclined position, it is possible to indicate the symbols clearly anddefinitely, to increase the size of the symbols without increasing thedimensions of the symbol indicator, and to reduce the dimensions of thesymbol indicator when it is not nessesary to increase the size of thesumbols, even if one-half portions of the adjacent symbol patterns inthe series overlap one another.

As distinguished from the Stevens, et al. patent mentioned above, in thepresent invention each symbol pattern is completely independent of eachother symbol pattern, even though the symbol patterns are made tooverlapeach other. Thus each symbol pattern is displayed indendently inthe symbol indication window and is complete in and of itself and is notformed by overlapping portions of two adjacent symbol patterns.

Another object of the invention is to provide a symbol indication deviceof the type described which permits to preclude a visual noise ordisturbance represented in the form of a dot or dots or a broken portionor portions in the indicated symbols which is caused by the fact thatone-half portions of the adjacent symbol patterns overlap one another.In the present invention, the occurrence of such noise is precluded byrefraining from arranging the adjacent symbol patterns to overlap oneanother and moving the symbol indicator a distance corresponding to thelength of one symbol pattern at a position in which a noise tends tooccur.

Another object of the invention is to provide a symbol indication deviceof the type described which proposes to obviate the problem ofoccurrence of a noise by utilizing a polarizing filter or otherpolarizer.

Still another object of the invention is to provide a symbol indicationdevice of the type described which comprises a noise preventerinterposed between the mask plate and the symbol indicator, such noisepreventer being adapted to be disposed in a noise occurring position ata required time so as to prevent the occurrence of a noise.

Still another object of the invention is to provide a symbol indicationdevice of the type described which is effective to prevent ommission ofthe rightwardly projecting portion of the horizontal member of thenumerical symbol 4, when such symbol is indicated by the device, bymeans of a special arrangement made in one of the symbol indicationwindows of the mask plate and a background pattern provided on thesymbol indicator.

A further object of the invention is to provide a symbol indicationdevice of the type described in which the mask plate, formed with symbolindication windows, is produced by punching from a metallic plate, andconnecting portions of the slots of the window are arranged to shieldnoise producing portions of a symbol pattern on the symbol indicatorwhereby the provision of the connecting portions of the window canprevent further occurrences of a noise.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of aclock of the digit indication type comprising one embodiment of thisinvention;

FIG. 2 is a left side view of the clock of FIG. 1 with certain portionsthereof being broken away;

FIG. 3 is a front view of one form of the mask plate according to thisinvention;

FIG. 4 is fragmentary developmental view showing the construction of oneform of the symbol indicator according to this invention and the mannerin which each symbol pattern of the symbol indicator is disposedrelative to the mask plate;

FIG. 5 is a plan view of the symbols obtained by watching the symbolpatterns on the symbol indicator shown in FIG. 4 through one of thewindows in the mask plate shown in FIG. 3;

FIG. 6 is a fragmentary front view of a modified form of the mask plate;

FIG. 7 is a fragmentary developmental view showing a form of the symbolindicator provided with a series of symbols corresponding to the maskplate shown in FIG. 6 and the manner in which each symbol pattern of thesymbol indicator is disposed relative to the mask plate;'

FIG. 8 is a plan view of the symbols obtained by watching the symbolpatterns on the symbol indicator shown in FIG. 7 through the mask plateshown in FIG.

FIG. 9 is a fragmentary developmental view of another modified form ofthe symbol indicator according to this invention, showing the manner inwhich each symbol pattern of the symbol indicator is disposed relativeto the mask plate;

FIG. I0 is a side view of the drive means for the symbol indicator;

FIG. II is a plan view of the symbols obtained by watching the symbolpatterns or the symbol indicator shown in FIG. 9;

FIG. 12 is a fragmentary front view of a modified form of the mask plateaccording to this invention;

FIG. 13 is a fragmentary developmental view of another modified form ofthe symbol indicator corresponding to the mask plate shown in FIG. 12showing the manner in which each symbol pattern of the symbol indicatoris disposed relative to the mask plate;

FIG. 14 is a plan view of the symbols obtained by watching the symbolpatterns on the symbol indicator shown in FIG. 13 through the mask plateshown in FIG. 12;

FIG. 15 is a perspective view of noise prevention means and drive meanstherefore according to this invention;

FIG. 16 is a front view showing the manner in which the noise preventionmeans shown in FIG. 15 operates;

FIG. 17 is a fragmentary developmental view of a modified form of thesymbol indicator adapted to cooperate with the noise prevention meansshown in FIG. 15;

FIG. 18 is a fragmentary front view of still another form of the maskplate according to this invention;

FIG. 19 is a fragmentary developmental view of still another modifiedform of the symbol indicator corresponding to the mask plate shown inFIG. 18, showing the manner in which each symbol pattern of the symbolindicator is disposed relative to the mask plate; and

FIG. 20 is a plan view of the symbols obtained by watching the symbolpatterns on the symbol indicator shown in FIG. 19 through the mask platein FIG. 18 and the manner in which each symbol pattern of the symbolindicator is disposed relative to the mask plate.

DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1, there is shown a clockof the digit indication type incorporating therein the presentinvention. It is to be understood that the invention can haveapplication in apparatus in which letters and numberical symbols arerequired to be indicated, in addition to clocks. The clock comprises acase 1 having secured to its front side a cover 2 made of glass, plasticor other transparent material, and a mask plate 3 made of metal orplastic.

In FIG. 3, the mask plate 3 is shown as being formed therein with foursymbol indication windows 4a, 4b, 4c and 4d each having an upright baseline 0 disposed in an inclined position. It will be seen that while thewindow 4a comprises only one inclined upright relatively narrow andelongated quadrilateral slot, the windows 4b, 4c and 4d each comprisethree horizontal slots and two inclined upright slots disposed onopposite sides of the horizontal slits. The invention will be describedas using the windows 4b, 4c and 4d which will be referred to as windows4.

A symbol indicator 5 shown in cylindrical form in FIG. 2 is made ofplastic or other transparent material and has a series of symbolpatterns 6 representing the digits 1, 2, 3, 4, 5, 6, 7, 8 and 9 printedor otherwise superposed on its peripheral surface. The series of symbolspatterns 6 are shown in developmental form in FIG. 4. Although only oneseries of symbol patterns is shown in FIG. 4, it is to be understoodthat actually the number of series of symbol patterns superposed on thesymbol indicator 5 corresponds to that of the window 411 and windows 4in the mask plate 3. The symbol indicator 5 is disposed rearwardly ofthe mask plate 3 as shown in FIG. 2 and adapted to be driven angularlyintermittently by suitable means as subsequently to be described.

A series of symbol patterns 6 cooperates with one of the symbolindication windows 4 of the mask plate 3 to indicate symbols. The baseline of each symbol pattern is inclined in the same manner as that ofeach window 4, so that each symbol pattern is disposed in one section ofthe symbol indicator 5 corresponding to one of the windows 4. It shouldbe noted that the series of symbol patterns is arranged on the symbolindicator 5 in such manner that the upper portion of the first symbolpattern in the series overlaps the lower portion of the second symbolpattern whose upper portion overlaps the lower portion of the thirdsymbol pattern and so on and so forth. Thus, one-half portions of theadjacent symbol patterns in theseries overlap one another.

In FIG. 4, a solid line bar or bars of each symbol pattern serve to fillthe portions of the slots of the window which are not required toindicate the respective symbol while a broken line bar or barscorrespond to the portions of the slots of the window which are used toindicate the respective symbol. The broken line bars are phantom linesand are not actually printed on the symbol indicator.

All the symbols can be indicated in the window as negative or positivesymbols. When the symbols indicated are referred to as being negativesymbols, it is meant that the symbols seen through the window arelighter in color than the surface of the mask plate.

When the symbols indicated are referred to being positive symbols, itmeans that the symbols are darker in color than the surface of the maskplate. When it is desired to indicate any symbol as a negative symbol,those portions of the slots of the window which are not required forindicating the respective symbol are filled and lost to view by thesolid line bars of the respective symbol pattern which are painted inthe same color as the surface of the mask plate. Conversely, when it isdesired to indicate any symbol as a positive symbol, those portions ofthe section of the symbol pattern on the symbol indicator whichcorrespond to the broken line bars in FIG. 4 corresponding to theportions of the slots of the window which are required for indicatingthe respective symbol are painted in a color darker than that of thesurface of the mask plate.

When the symbol indicator 5 is driven intermittently by one pitch(through 36, for example) as by clockwork, digits as shown in FIG. 5 canbe indicated in the window 4 by the symbol indicator 5 cooperating withthe mask plate 3. Imaginary center lines a, b, g of sections of thesymbol indicator 5 are successively brought into index with theimaginary center line of one of the symbol indication windows 4, of thethree horizontal slits and two inclined upright slots type, in the maskplate 3 as the symbol indicator 5 is intermittently driven and moved. Asa result, digits 1, 2, 3 7 are successively indicated in this order inthe window 4 as the portions of each symbol pattern painted in the samecolor as the surface of the mask plate 3, or the solid line bars, fillthose portions of the slots not required for indicating the symbols andshield them from sight.

The clock of the digit indication type shown in FIG. 1 has a lamp builtin the symbol indicator 5 so that the time can be readily indicated andperceived even in the dark at night because the digits can be seen insharp relief. When illuminated from outside the symbol indicator 5, thesymbol indicating window 4 disposed in an inclined position may beformed in the mask plate 3 as shown in FIG. 6 to comprise threehorizontal slots and four inclined upright slots, and the portions ofthe surface of the symbol indicator 5 which are required for indicatingthe symbols may be painted with a fluorescent paint to provide thesymbols patterns 6 as shown in FIG. 7. By this arrangement, it ispossible to give indication of digits as shown in FIG. 8.

While the invention has been shown and described as being incorporatedin a clock of the digit indication type, it will be understood that manyof the English letters such, for example as C, E, F, H, I, J, L, O, Pand S can be indicated readily as can be surmised from the fact that theletters and l are similar to the digits 0 and l and that the letter Ecan be indicated by inverting the digit 3.

The surface of the symbol indicator in cylinder form is shown indeveloped form in FIG. 4. It will be appreciated that an indicator thatcan be developed in this way, or a belt. for example, can be used toindicate symbols in the same manner as the cylindrical indicator is usedin the present invention. It will also be appreciated that the symbolindication windows 4 for indicating numerical symbols, English lettersor other symbols are not limited to the type comprising three horizontalslots and two inclined upright slots and that many other types ofwindows can be employed.

As aforementioned, according to this invention, at least a series'ofsymbols is superposed on the surface of the indicatorS in the form of acylinder or a belt in such manner that one-half portions of the adjacentsymbol patterns overlap one another. This offers the advantage of beingable to indicate the symbols in a size which is twice as large as wouldbe the case if the adjacent symbol patterns on the symbol indicator didnot overlap one another.

However, some disadvantage is associated with the arrangement in whichinclined symbol patterns 6 are arranged such that they overlap oneanother and are disposed equidistantly as shown in FIG. 4. Morespecifically, the symbols as seen through the window 4 will have brokenportions in them as seen in the digits 2, 3, 5, 6 and 0 shown in FIG. 5,or redundant dot or dots in the digits 1, 2 and 4 shown in FIG. 8. Thesedefects in the indicated symbols constitute a visual noise which looksstrange tothe viewer.

The noise in the form of broken portions of the indicated digits occursin portions 6A, 6B, 6C, 6D and 6E shown in FIG. 4. It will be observedthat these broken portions occur in portions of the symbol patternswhere the solid line bar of one symbol pattern and the broken line barof another symbol pattern, which are disposed in adjacent overlappingrelationship, cross each other. The occurrence of a noise can beprecluded by several means according to this invention.

In order to obviate the aforementioned disadvantage, the symbol patterns6 can be arranged in an inclined position on the surface of the symbolindicator 5 in such manner that the adjacent symbol patterns overlap oneanother unequidistantly as shown in FIG. 9.

More specifically, the symbol indicator 5 shown in FIG. 10 is rotatablysupported by a rotary shaft 7 and has a star-shaped cam plate or ratchet8 integrally connected to one side thereof. The symbol patterns 6 areperipherally superposed on the outer periphery of the symbol indicator 5in an inclined position in such manner that the adjacent symbol patternsoverlap one another unequidistantly as shown in FIG. 9. Wedgeshapedcutouts 9 are formed at one end of the outer periphery of the indicator5 to receive therein a keep lever 10 so as to regulate the position ofangular rotation of the symbol indicator 5.

A sickle-shaped lever or pawl 11, which is supported by a shaft forpivotal movement, is urged by a spring 13 to pivot clockwise be heldstationary by a fixed pin 14. A rotary disk 15, which is angularlyrotated by a clockwork, has attached to one end thereof a plurality ofpins 16 which are spaced different radial distances from the center ofthe disk 15 but disposed angularly adjacent one another with respect tothe center of the disk 15. The pins 16 are engaged by a projection 11aformed in the lever 11.

When the rotary disk 15 is rotated angularly intermittently counterclockwise by the clockwork, one of the pins 16 presses against theprojection 11a in the lever 11 and causes the lever to pivot counterclockwise against the biasing force of the spring 13. This results in afront end 11b of the lever pressing the cam plate 8 so as to angularlyrotate the symbol indicator 5 counter clockwise.

Since the symbol patterns 6 are arranged to overlap one another anddisposed unequidistantly from one another on the outer periphery of thesymbol indicator 5 as aforementioned, it is required to change the angleof intermittent rotation of the symbol indicator in order to bring eachsymbol pattern 6 into index with the symbol indication window 4. Thischange is effected by the arrangement of cam plate 18 and pins 16. Sincethe pins 16 are disposed unequidistantly from the center of rotation ofthe rotary disk 15, the angle of pivotal movement of the lever 11 causedby the intermittent angular rotation of the rotary disk 15 varies eachtime the rotary disk 15 rotates. The cam plate 8 is formed on its outerperiphery with projections 8a which are disposed unequidistantly fromone another and in accord with the pivotal movements caused by the pins16 on the rotary disk 15. By this arrangement, the symbol indicator 5can be rotated angularly to bring one symbol 6 after another into indexwith the symbol indication window 4 each time the rotary disk 15 isrotated.

Thus, if the symbol indicator 5 is watched by the viewer through thesymbol indication window 4, symbols as shown in FIG. 11 can be seen inthe symbol indication window 4, and no visual. noise caused by thebreaking of the figures or addition of an unnecessary dot or dots occurssuch as seen in the'digits 2, 3 shown in FIG. 5.

The aforementioned disadvantage associated with the arrangement in whichthe inclined symbol patterns 6 are arranged such that they overlap oneanother and are disposed equidistantly from one another as shown in FIG.4 is thus obviated by arranging the inclined symbol patterns such thatthey overlap one another but are disposed unequidistantly from oneanother and driving the symbol indicator angularly intermittently withirregular intervals. It is to be noted that, irrespective of whether thesymbol patterns are disposed equidistantly or unequidistantly from oneanother, the indication device according to this invention permits eachsymbol to be indicated through the window in a size which is twice asgreat as would be the case if the symbol patterns were not caused tooverlap one another without increasing the dimensions of the device.Besides, the indicated symbols are free from any visual noise, therebypermitting the indicated symbols to be seen more clearly and readily.

The aforementioned disadvantage can be obviated by other means. Thatis,'the disadvantage can be obviated optically by using polarizers. Itwill be needless to say that light in a transverse wave motion, and thatnatural light is a transverse wave motion and consists of vibrationstaking place in all directions at right angles to the direction of itspath. When natural light is passed through an artifical polarizing plateor the like, it is possible to botain plane polarized light consistingof vibrations in only a specific direction which is at right angles tothe direction of its path. Means for converting natural light into planepolarized light. such for example as an articifial polarizing plate. isreferred to as a polarizer. A plane comprising the direction of the pathof plane polarized light and the direction of its vibrations is referredto as a polarization plane. Plane polarized light has a property suchthat it passes through a polarizer having a polarization plane which isparallel to its polarization plane but not through a polarizer having apolarization plane which is perpendicular thereto.

According to the invention, four polarizers 17A1, 17A2, 1781 and 1782are mounted as shown in FIG. 12 in the portions of the slots of thewindow of the mask plate 3 which correspond to the portions 6A, 6B,

6C and 6D of the symbol patterns on the symbol indicator in FIG. 4 whilefive polarizers 18A1, l8A2, 18A3, 1881 and 1882 are mounted as shown inFIG. 13 in the portions 6A, 6B, 6C, 6D and 6E of the symbol patterns onthe symbol indicator 5. It will be noted that, since the portions 6D and6E overlap one another, only four polarizers need be mounted in thecorresponding portions of the slots of the window.

The polarizers are mounted such that the polarizers 17A1 and 17A2 andthe polarizers 18Al, 18A2 and 18A3 have polarization planes which areparallel to one another, and the polarizers 17B1 and 17B2 and thepolarizers 1881 and 18B2 have polarization planes which are parallel toone another, but the polarization planes of the polarizers 17A1 and 17A2and the polarizers 1781 and 1782 are perpendicular to one another (andthe polarization planes of the polarizers 18A1, 18A2 and 18A3 and thepolarizers 1881 and 18B2 are perpendicular to one another too).

When the indicator 5 having the polarizers 18 mounted in the portions6A, 6B, 6C, 6D and 6E of the symbol patterns thereof is rotated anularlyintermittently as by clockwork, center lines (a), (b) (g) of the symbolpatterns on the symbol indicator 5 successively are brought into indexwith the center of the window 4 in the mask plate 3, permitting thedigits 1, 2, 3 O to be indicated successively through the window asshown in FIG. 14.

Let us assume that it is desired to indicate the digit 1 in the window,for example. In this case, the center line (a) of the symbol pattern onthe symbol indicator 5 shown in FIG. 13 is indexed with the center ofthe window 4 shown in FIG. 12. In the portions of the slots of thewindow 4 where the polarizers l7Al, 17A2 and 1782 are mounted, naturallight is converted into plane polarized light but this has no effect onthe viewer who watches the indicated digit. However, in the portion ofthe slots of the window where the polarizer 1782 is mounted, thepolarizer 17B2 overlies the polarizer 18Al mounted in the portion 6A ofthe symbol pattern 6 on the symbol indicator 5 and light is interceptedby them because the polarization surfaces of these polarizers areperpendicular to one another. Thus, the flawless digit 1 shown in FIG.14 can be seen through the window.

If the symbol indicator 5 is angularly moved and the center line (b) ofthe symbol indicator 5 shown in FIG. 14 is indexed with the center lineof the window in the mask plate 3, then the portions of the slits of thewindow 4 in which the polarizers 17A2 and 1782 are mounted have noeffect on the viewer watching the device, but the polarizer 17Al in theslit of the window overlaps the polarizer 18A1 in the portion 6A of thesymbol indicator 5 and the polarizer 1781 in the window overlaps thepolarizer 18A2 on the symbol indicator. Since the polarizers 17A1 and18A] have polarization planes which are parallel to one another, lightis permitted to pass therethrough and nothing is seen to exist therein.However, since the polarizers 1781 and 18A2 have polarization planeswhich are perpendicular to one another. the light incident thereon isintercepted, so that the perfect digit 2 as shown in FIG. 14 can beseenin the window.

In like manner, the polarizers 18A2, 18A3, 18B1 and 18B2 mounted in theportions 613, 6C, 6D and 615 of the symbol indicator 5 cooperate withthe polarizers l7Bl, 17A1; 1782 and 17A2 mounted in the slots of thewindow 4 in indicating other symbols than I and 2 to intercept light andpermitting light to pass through the polarizers, so that a visual noisein the form of occurrences of broken portions in the indicated digitscan be precluded.

In the illustrated embodiment, the digits are indicated through thewindow by concealing, by means of the symbol patterns and thepolarizers, the portions of the slots of the window 4 which are notrequired for indicating the respective digits. It is to be understood,however, that the digits can be indicated through the window byrevealing the portions of the slots of the window which are required forindicating the respective digits.

As aforementioned, polarizers are mounted in those portions of theoverlapping symbol patterns of the symbol indicator which cross oneanother and in those portions of the slots of the symbol indicationwindow in the mask plate which correspond to the aforesaid intersectionsof the symbol patterns to eliminate the occurrences of broken portionsin the digits indicated in the window. This arrangement is effective topreclude the occurrence ofa visual noise while permitting to indicatesymbols in the window in a size twice as large as would otherwise be thecase, without increasing the dimensions of the indication device.

The noise can be eliminated by cam means according to this invention.When ancillary members and cam means are used to prevent occurrences ofa noise, the

' symbol patterns 6 on the symbol indicator are painted such that noiseproducing portions 28A, 28B, 28C, 28D and 28E (FIG. 17) are leftunpainted. As shown in FIG. 15, cylindrical cams I9 and constituting cammeans-are formed integrally on one end of the symbol indicator 5, suchcylindrical cams I9 and 20 being formed on their outer periphery with aplurality of peripheral cam grooves 21. Four ancillary members 22, 23,24 and constituting noise prevention means are formed of a resilientmaterial and connected at one end to a part (not shown) such that theynormally engage, at projections 22A, 23A, 24A and 25A providedsubstantially in the middle, the peripheral surfaces of the cylindricalcams l9 and 20.

The ancillary members 22 and 25, which are each formed with a hook atthe forward end engage the peripheral surface of the clyindrical cam 19while the ancillary members 23 and 24, which are not formed with a hookat their forward end, engage the peripheral surface of the cylindricalcam 20. When the projections 22A, 23A, 24A and 25A drop into peripheralcam grooves 21, the forward ends of the ancillary members move topositions shown at 22a, 23a, 24a and 25a in phantom lines in FIG. 16.

Let us assume that the symbol indicator 5 is angularly intermittentlydriven so as to successively bring the center lines (a), (b), (c) (g) onthe symbol indicator 5 (See FIG. 13) into index with the center of thewindow 4 in the mask plate 3. The peripheral cam grooves 21 arepositioned such that the projections 22A and 24A drop into theperipheral cam grooves 21 when the center line (a) is indexed with thecenter line of the window 4, the projection 22A drops into one of theperipheral cam grooves 21 when the center line (b) is indexed with thecenter of the window 4, the projection 23A when the center line (d) isindexed with the center of the window 4, and the projection 24A when thecenter line (g) is indexed with the center of the window 4.

The forward ends of the ancillary members 22 to 25 are painted in thesame color as the mask plate 3.

7 In operation, when the angular intermittent rotation of the symbolindicator 4 brings the center line (a) shown in FIG. 17 into index withthe window 4 in the mask plate 3, the projections 22A and 24A of theancillary members 22 and 24 respectively drop into the peripheral camgrooves 21 and the ancillary members 22 and 24 move to the positions 22aand 24a shown in FIG. 16 respectively. A comparison of FIG. 16 with FIG.17 shows that the forward ends of the ancillary members 22 and 24 havemoved to positions designated 28A and 28E respectively in which theycover portions. In this way, the portions of the slots of the window 4which are not used to indicate the digit 1 are concealed by the forwardends of the ancillary members 22 and 24, so that the flawless digit 1shown in FIG. 14 can be indicated in the window 4.

When the center line (b) on the symbol indicator 5 is next brought intoindex with the center of the window 4, the ancillary member 22 moves sothat its forward end 22A is disposed in a portion designated 28B in FIG.17, so that the portion of the slots of the window which is not used toindicate the digit 2 is concealed by the forward end 22A of theancillary member 22.

The next angular rotation of the symbol indicator 5 brings the centerline (c) into index with the center of the window 4. In this case, noancillary members move.

In indicating the digits following 3, the forward end portions of theancillary members 25 and 24 move to positions designated by 28C and 28Drespectively on the symbol indicator and the forward end of theancillary member 24 moves to a position designated 28E. This permits theflawless digits shown in FIG. 14 to be indicated in the window 4.

FIG. 18 shows a modified form of the windows 4, of the three horizontalslits and two inclined upright slots type, in which the intermediatehorizontal slots project htrough and out of the right inclined uprightslot. The use of this form of windows 4 permits the digit 4 to beindicated in perfect form shown in FIG. 20.

The rightwardly projecting portion of the intermediate slit is not usedexcept when the digit 4 is indicated,

so that this portion is concealed by portions 6A of the symbol patterns6 shown in FIG. 19 when digits other than 4 are indicated. The use ofthe type of window 4 shown in FIG. 18 enables the horizontal memberofthe digit 4 to be indicated clearly as projecting rightwardly throughthe vertical member. This is the natural form ofthe digit 4, so that thedigit 4 indicated in the window 4 can be understood correctly. Besides,since the window 4 is inclined toward the right, the use of the symbolpatterns 6 arranged in adjacent overlapping relationship does notinterfere with the indication of digits in the window.

When the mask plate 3 according to this invention is formed by punchingfrom a metallic plate, the portions of the slots of the window whichcorrespond to the noise producing portions in the symbol patterns on thesymbol indicator can be used as connecting portions so as to preventdislodging of the center shield portions. As shown in FIG. 12, there arefour such portions in the window, one portion each in the upper, lower,left and right portions. It will be evident that the use of suchportions as connecting portions is advantageous.

What I claim is:

1. A symbol indication device comprising, in combination, a mask plateformed with at least one symbol indication window comprising at leastone slit and having a standard line which is inclined with respect tothe perpendicular, a symbol indicator carrying thereon at least oneseries of symbol patterns adapted to cooperate with said symbolindication window to indicate the symbols in succession in said symbolindication window, said series of symbols being inclined with respect tothe perpendicular and the symbol pattern in the series being arrangedsuch that half portions of at least some adjacent symbol patternsoverlap one another, and drive means for intermittently driving 'saidsymbol indicator relative to said mask plate through a distancesufficient to bring the symbol patterns successively into indexedrelation with the symbol indication window, whereby the symbols can beindicated successively in the symbol indication window in the maskplate; said symbol patterns on said symbol indicator being arranged in amanner such that those symbol patterns which are adjacent each other andwhich are likely to produce a visual noise when indicated through thesymbol indication window do not overlap each other, the symbol patternsbeing arranged at unequal distances from each other, said drive meansdriving said symbol indicator relative to said mask plates throughunequal distances corresponding to the unequal spacings of said symbolpatterns, whereby those symbol patterns likely to produce a visualnoise, if overlapped, are brought individually into indexed relationwith the symbol indication window.

2. A symbol indication device comprising, in combination, a mask plateformed with at least one symbol indication window comprising threevertically spaced horizontal slots interconnected at their ends by twoupright slots parallel to a standard line which is inclined at a presetsmall angle with respect to the perpendicular, and forming a closedquadrilateral loop divided in half by the intermediate slot of saidhorizontal slots; a symbol indicator carrying thereon at least oneseries of symbol patterns each including at least one relatively narrowand elongated rectilinear bar area alignable with at least a portion ofat least one of said slots so that said symbol patterns are adapted tocooperate with said symbol indication window to indicate the symbols insuccession in said symbol indication window; the symbol patterns of saidseries being inclined at said preset small angle with respect to theperpendicular, and the symbol patterns in the series being arranged suchthat less than half portions of at least some adjacent symbol patternsoverlap one another; the vertical distance between centers of adjacentsymbol patterns being in excess of half the height of each symbolpattern; and drive means operable to intermittently drive said symbolindicator relative to said mask plate through a distance equal to thevertical distance between centers of adjacent symbol patterns andsufficicient to bring the symbol patterns successively into indexedrelation with the symbol indication window, whereby the symbols can beindicated successively in the symbol indication window in the maskplate.

3. A symbol indication device as set forth in claim 2 wherein saidseries of symbol patterns on said symbol indicator have portions whichare not used for indicating symbols in the symbol indication window andwhich are the same color as the surface of said mask plate.

4. A symbol indication device as set forth in claim 2 wherein saidseries of symbol patterns on said symbol indicator have portions whichare used for indicating symbols in the symbol indication window andwhich are a color different from the color of the surface of said maskplate. 7

5. A symbol indication deviceasset forth in claim 2 wherein said symbolindicator is cylindrical in shape.

6. A symbol indication device as set forth in claim 2 wherein saidsymbol indicator is in belt form.

7. A symbol indication device as set forth in claim 2 wherein arespective polarizer is mounted at least in one visual noise producingportion of the symbol patterns on said symbol indicator and in thesymbol indication window of the mask plate.

8. A symbol indication device as set forth in claim 2 wherein visualnoise prevention means is provided between said mask plate and saidsymbol indicator to conceal noise producing portions whereby productionof a visual noise can be precluded as the symbol indicator isintermittently moved.

9. A symbol indication device as set forth in claim 8 wherein said noiseprevention means comprises levers adapted to operate in synchronism withsaid symbol indicator.

10. A symbol indication device as set forth in claim 2 wherein theintermediate horizontal slot projects through the right inclined uprightslot and rightwardly thereof.

11. A symbol indication device as set forth in claim 2 wherein said maskplate is formed, at each noise producing portion of said symbolindication window, with a connecting member to support center shieldportions. t

1. A symbol indication device comprising, in combination, a mask plateformed with at least one symbol indication window comprising at leastone slit and having a standard line which is inclined with respecT tothe perpendicular, a symbol indicator carrying thereon at least oneseries of symbol patterns adapted to cooperate with said symbolindication window to indicate the symbols in succession in said symbolindication window, said series of symbols being inclined with respect tothe perpendicular and the symbol pattern in the series being arrangedsuch that half portions of at least some adjacent symbol patternsoverlap one another, and drive means for intermittently driving saidsymbol indicator relative to said mask plate through a distancesufficient to bring the symbol patterns successively into indexedrelation with the symbol indication window, whereby the symbols can beindicated successively in the symbol indication window in the maskplate; said symbol patterns on said symbol indicator being arranged in amanner such that those symbol patterns which are adjacent each other andwhich are likely to produce a visual noise when indicated through thesymbol indication window do not overlap each other, the symbol patternsbeing arranged at unequal distances from each other, said drive meansdriving said symbol indicator relative to said mask plates throughunequal distances corresponding to the unequal spacings of said symbolpatterns, whereby those symbol patterns likely to produce a visualnoise, if overlapped, are brought individually into indexed relationwith the symbol indication window.
 2. A symbol indication devicecomprising, in combination, a mask plate formed with at least one symbolindication window comprising three vertically spaced horizontal slotsinterconnected at their ends by two upright slots parallel to a standardline which is inclined at a preset small angle with respect to theperpendicular, and forming a closed quadrilateral loop divided in halfby the intermediate slot of said horizontal slots; a symbol indicatorcarrying thereon at least one series of symbol patterns each includingat least one relatively narrow and elongated rectilinear bar areaalignable with at least a portion of at least one of said slots so thatsaid symbol patterns are adapted to cooperate with said symbolindication window to indicate the symbols in succession in said symbolindication window; the symbol patterns of said series being inclined atsaid preset small angle with respect to the perpendicular, and thesymbol patterns in the series being arranged such that less than halfportions of at least some adjacent symbol patterns overlap one another;the vertical distance between centers of adjacent symbol patterns beingin excess of half the height of each symbol pattern; and drive meansoperable to intermittently drive said symbol indicator relative to saidmask plate through a distance equal to the vertical distance betweencenters of adjacent symbol patterns and sufficicient to bring the symbolpatterns successively into indexed relation with the symbol indicationwindow, whereby the symbols can be indicated successively in the symbolindication window in the mask plate.
 3. A symbol indication device asset forth in claim 2 wherein said series of symbol patterns on saidsymbol indicator have portions which are not used for indicating symbolsin the symbol indication window and which are the same color as thesurface of said mask plate.
 4. A symbol indication device as set forthin claim 2 wherein said series of symbol patterns on said symbolindicator have portions which are used for indicating symbols in thesymbol indication window and which are a color different from the colorof the surface of said mask plate.
 5. A symbol indication device as setforth in claim 2 wherein said symbol indicator is cylindrical in shape.6. A symbol indication device as set forth in claim 2 wherein saidsymbol indicator is in belt form.
 7. A symbol indication device as setforth in claim 2 wherein a respective polarizer is mounted at least inone visual noise producing portion of the symbol patterns on said symbolindicator and in the symbol indication window of the mask Plate.
 8. Asymbol indication device as set forth in claim 2 wherein visual noiseprevention means is provided between said mask plate and said symbolindicator to conceal noise producing portions whereby production of avisual noise can be precluded as the symbol indicator is intermittentlymoved.
 9. A symbol indication device as set forth in claim 8 whereinsaid noise prevention means comprises levers adapted to operate insynchronism with said symbol indicator.
 10. A symbol indication deviceas set forth in claim 2 wherein the intermediate horizontal slotprojects through the right inclined upright slot and rightwardlythereof.
 11. A symbol indication device as set forth in claim 2 whereinsaid mask plate is formed, at each noise producing portion of saidsymbol indication window, with a connecting member to support centershield portions.